A siphon toilet is a new type toilet that is better than the traditional direct water type flushing toilet, the siphon toilet is disposed with a complete siphon pipe of S shape on the side, the urinal wall has gentle slope, comparing to the direct water type flushing toilet, it improves the noise problem and it also has strong washing-out performance and large flushing surface. There are three types of siphon toilets in existing market: one type is common siphon toilet, a second type is spray siphon toilet and a third type is vortex siphon toilet. Therein, spray siphon type toilet is added with a spray subsidiary pipe and a spray hole at the bottom of the urinal of the toilet comparing to the common siphon toilet, the spray hole directly faces to the washing-out hole of the toilet; when water drains out, a part of water flushes out of the flushing holes arranged at the periphery of the top portion of the urinal of the toilet to wash the inner wall of the urinal of the toilet body, the other part of water sprays out of the spray hole at the bottom of the urinal to wash the bottom of the urinal of the toilet, it also forms siphon effect with the siphon pipe. Significantly, the spray siphon toilet has a larger flushing impact based on the siphon function to wash out the dirt fast, so that this type of siphon toilet has stronger washing-out function.
However, existing spray type siphon toilet is provided that the water diversion position of the flushing holes and the spray hole is disposed above the water seal surface of the urinal of the toilet (the water diversion position is usually disposed at the rear side of the top portion of the urinal of the toilet), as the flushing holes at the top portion of the urinal are connected to the outside air, under the work of the atmosphere pressure, only the pipe below the water seal surface of the urinal keeps water, but the pipe between the water seal surface of the urinal and the drain valve of the toilet is full of air, therefore, after the drain valve of the toilet drains, water firstly fills the pipe between the water seal surface of the urinal and the drain valve of the toilet. during initial period, when water is filling to the pipe of the toilet, part of water flows out of the siphon pipe of the toilet, it makes that the actual flushing potential energy is lower than the initial potential energy, so that the siphon pipe can not immediately form siphon, thus resulting in water wasting. In addition, after the drain valve of the toilet starts to drain, water firstly fills the pipe between the water seal surface of the urinal and the drain valve of the toilet, then flowing out of the flushing holes at the top portion of the urinal, it also results in bad flushing performance to the inner wall of the urinal. Especially to a toilet with lower water tank, the influence is significant.